It is generally desirable to reduce duty cycle losses in a mass spectrometer system. One source of duty cycle losses is in waiting for ions of different mass to charge ratios (m/z), ejected from a multipole ion guide such as a quadrupole, to reach their destination, generally an entry point of a mass detector (e.g. a time of flight (ToF) detector). In general, ions with high m/z travel at slower speed than ions with a lower m/z. In orthogonal TOF instrument the duty cycle is limited by the repetition rate of the TOF extraction pulses which are in turn limited by the speed at which the heavy ions are travelling. If the repetition rate is increased beyond an optimal value heavier ions are not properly sampled and/or lost. This problem can be addressed by causing ions trapped in a quadrupole ion guide to be ejected in a desired sequence, for example in order of m/z ratio starting with heavier ions, such that they arrive at a desired location in space simultaneously, for example at the extraction region of the ToF detector, and with the same kinetic energy. Such a technique can be used in other applications, such as filling ion traps (e.g. FT-ICR traps, Orbitraps, and Quadrupole ion traps) In any event, it is known that such a solution can be provided by simultaneous application of both radio-frequency (RF) and alternating (AC) voltages to the quadrupole electrodes. However, circuits for simultaneous application of RF and AC currents to the quadrupole can be quite complex.